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authorOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>2018-07-20 12:01:48 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2018-07-26 23:05:14 -0400
commit932d6562179efe8e2460a0343dbe0fcacf288a9e (patch)
treeedaf27dad5042f971a9f098ca7c6217132e4d08c /drivers/xen/gntdev-dmabuf.c
parent1d314567553883d9f606cc59e8e66f465a4b6ccd (diff)
downloadlinux-932d6562179efe8e2460a0343dbe0fcacf288a9e.tar.bz2
xen/gntdev: Add initial support for dma-buf UAPI
Add UAPI and IOCTLs for dma-buf grant device driver extension: the extension allows userspace processes and kernel modules to use Xen backed dma-buf implementation. With this extension grant references to the pages of an imported dma-buf can be exported for other domain use and grant references coming from a foreign domain can be converted into a local dma-buf for local export. Implement basic initialization and stubs for Xen DMA buffers' support. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen/gntdev-dmabuf.c')
-rw-r--r--drivers/xen/gntdev-dmabuf.c177
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
new file mode 100644
index 000000000000..af782c0a8a19
--- /dev/null
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Xen dma-buf functionality for gntdev.
+ *
+ * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include <xen/xen.h>
+#include <xen/grant_table.h>
+
+#include "gntdev-common.h"
+#include "gntdev-dmabuf.h"
+
+struct gntdev_dmabuf_priv {
+ /* List of exported DMA buffers. */
+ struct list_head exp_list;
+ /* List of wait objects. */
+ struct list_head exp_wait_list;
+ /* This is the lock which protects dma_buf_xxx lists. */
+ struct mutex lock;
+};
+
+/* DMA buffer export support. */
+
+/* Implementation of wait for exported DMA buffer to be released. */
+
+static int dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd,
+ int wait_to_ms)
+{
+ return -EINVAL;
+}
+
+static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
+ int count, u32 domid, u32 *refs, u32 *fd)
+{
+ *fd = -1;
+ return -EINVAL;
+}
+
+/* DMA buffer import support. */
+
+static struct gntdev_dmabuf *
+dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
+ int fd, int count, int domid)
+{
+ return ERR_PTR(-ENOMEM);
+}
+
+static u32 *dmabuf_imp_get_refs(struct gntdev_dmabuf *gntdev_dmabuf)
+{
+ return NULL;
+}
+
+static int dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
+{
+ return -EINVAL;
+}
+
+/* DMA buffer IOCTL support. */
+
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
+ struct ioctl_gntdev_dmabuf_exp_from_refs __user *u)
+{
+ struct ioctl_gntdev_dmabuf_exp_from_refs op;
+ u32 *refs;
+ long ret;
+
+ if (use_ptemod) {
+ pr_debug("Cannot provide dma-buf: use_ptemode %d\n",
+ use_ptemod);
+ return -EINVAL;
+ }
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ if (unlikely(op.count <= 0))
+ return -EINVAL;
+
+ refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL);
+ if (!refs)
+ return -ENOMEM;
+
+ if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = dmabuf_exp_from_refs(priv, op.flags, op.count,
+ op.domid, refs, &op.fd);
+ if (ret)
+ goto out;
+
+ if (copy_to_user(u, &op, sizeof(op)) != 0)
+ ret = -EFAULT;
+
+out:
+ kfree(refs);
+ return ret;
+}
+
+long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_exp_wait_released __user *u)
+{
+ struct ioctl_gntdev_dmabuf_exp_wait_released op;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ return dmabuf_exp_wait_released(priv->dmabuf_priv, op.fd,
+ op.wait_to_ms);
+}
+
+long gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_to_refs __user *u)
+{
+ struct ioctl_gntdev_dmabuf_imp_to_refs op;
+ struct gntdev_dmabuf *gntdev_dmabuf;
+ long ret;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ if (unlikely(op.count <= 0))
+ return -EINVAL;
+
+ gntdev_dmabuf = dmabuf_imp_to_refs(priv->dmabuf_priv,
+ priv->dma_dev, op.fd,
+ op.count, op.domid);
+ if (IS_ERR(gntdev_dmabuf))
+ return PTR_ERR(gntdev_dmabuf);
+
+ if (copy_to_user(u->refs, dmabuf_imp_get_refs(gntdev_dmabuf),
+ sizeof(*u->refs) * op.count) != 0) {
+ ret = -EFAULT;
+ goto out_release;
+ }
+ return 0;
+
+out_release:
+ dmabuf_imp_release(priv->dmabuf_priv, op.fd);
+ return ret;
+}
+
+long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_release __user *u)
+{
+ struct ioctl_gntdev_dmabuf_imp_release op;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ return dmabuf_imp_release(priv->dmabuf_priv, op.fd);
+}
+
+struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
+{
+ struct gntdev_dmabuf_priv *priv;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return ERR_PTR(-ENOMEM);
+
+ return priv;
+}
+
+void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv)
+{
+ kfree(priv);
+}